The invention relates to a device for recording information in at least one information volume in a track in a recordable area on a record carrier, which information volume comprises a start zone, a data zone and an end zone, which device comprises recording means for recording marks representing the information and control means for recording and retrieving position data indicative of the position of the recorded information volume.
The invention further relates to a method of recording information in at least one information volume in a track in a recordable area on a record carrier, which information volume comprises a start zone, a data zone and an end zone, which method comprises recording marks representing the information and position data indicative of the position of the recorded information volume.
The invention further relates to a record carrier having a track in a recordable area for recording at least one information volume, which information volume comprises a start zone, a data zone and an end zone, the track comprising marks representing the information and position data indicative of the position of the recorded information volume.
A device and method for recording information signals on a record carrier is known from U.S. Pat. No. 5,341,356 (PHN13661). The information is encoded in information blocks comprising data words and error correction words for correcting errors within the information block. The device comprises recording means for recording marks representing the information. The information of at least one information block is modulated to a modulated signal and recorded in the track at predefined locations indicated by preformed track position information. The device records the information formatted in successive volumes, also called sessions, in a multi-session layout. Each volume has a start zone, also called lead-in, a data zone, and an end zone, also called lead-out. The device has control means for recording and retrieving position data indicative of the position of the recorded information volumes. In particular in the lead-out a pointer is recorded for locating the start zone of the session. Further the lead-in contains information about the position of the lead-out of that session, and hence of the start zone of the next session (if any). For locating a specific session the device may locate the last recorded session by detecting the border of the unrecorded area and reading the last lead-out, and follow the chain of sessions to the start of the recorded area. Alternatively the device may read the lead-in of the first session, and follow the chain of sessions by reading the lead-in of the consecutive volumes. The time for accessing a specific session is determined by the amount of time required for jumping along said chain of sessions. In a write once type of record carrier like CD-R the position data cannot be overwritten.
It is an object of the invention to provide a more flexible system for recording the position data.
For this purpose, the device as described in the opening paragraph is characterized in that the control means comprise mapping means for recording at least one session map block in a session map zone, the session map block comprising the position data of closed sessions, a closed session being a completely recorded information volume, and detecting means for retrieving the session map block from said session map zone. The method as described in the opening paragraph is characterized in that the method comprises recording at least one session map block in a session map zone, the session map block comprising the position data of closed sessions, a closed session being a completely recorded information volume, and retrieving the session map block from said session map zone. The record carrier as described in the opening paragraph is characterized in that the record carrier comprises at least one session map block in a session map zone, the session map block comprising the position data of closed sessions, a closed session being a completely recorded information volume. This has the advantage that a map of the recorded session is available to the recording device. In particular this is advantageous for locating recorded data, e.g. files in a computer application, that have been deleted from the user content management data, e.g. according to an UDF file system. When such a deleted file has to be recovered, the device can access the earlier recorded sessions for retrieving earlier versions of the content management data, which still have the location data of the deleted data.
The invention is based on the following recognition. The inventors have seen that a substantial amount of the response time of a recording device to a request for accessing an earlier recorded session is due to the amount time required for retrieving position data of the session to be accessed. Subsequently the inventors have seen that the response time can be decreased by recording the information about the sessions in the session map area.
In an embodiment of the device the mapping means are arranged for recording consecutive session map blocks, and the session map block recorded last contains consecutive session items for each closed session. This has the advantage that the most up to date information about all recorded sessions is available in a single session map block. The response time of the device for accessing a session is reduced because only the last recorded session map block needs to be retrieved and processed.